Fluid coking



w. M. MILLER 2,946,741

FLUID COKING 2 sheets-sheet 1 July 26, 1960 Filed June 2l. 1956 July 26, 1960 Filed June 21, 1956 w. M. MILLER 2,946,741

FLUID COKING 2 Sheets-Sheet 2 AGENT United States Patent C FLmD coKING Walter M; Miller, Walnut Creek, Calif., .assignor to `Tidewater-.Oil Company,acorporation of Delaware' Filed June 21, .1956, ser. yis'r0.r592;924

' 4 claims.y (onzas- 127)v This invention relatesv tot improvements inl method: and'.v apparatus-for' effecting the conversionof heavy petroleum stocks. to: more desirablev -loweraboiling products by afluidized coking process.

Pilot.` and commercial .plant experiences have demon strated that the fluidizing and circulation oficokev in any operation utilized; iu petroleum; refineries to upgrade heavy residual oils to lighter products. useful, in the manufacture-of gasoline, etc., presents no problem when theproper ratios of feed, coke,v temperature, and' steam. are: used.. Inthe operation, solid coke"` particles, fluid-v.

ized'by. steam andother vapors, arecycled between.4 ai

bu-rner (heater) unit and a coking `(reactor) unit. In.

the:burnerY unit',- somezvcoke'r is. burnedrin. orderto heat the: rest` oft the. coke, and. the` hot coke; is` conveyedY as. smallev solid particles ina iiuidized stream: back to'the reactor unit. ln the. reactor, fthe heavy oil sprayed.

ony the. hot coke, and .the heat'cra'cksthe' oil into anc,

eflluentmist` with concomitant formation. offadditional: coke; whichA is depositedonithe. coke particles', enlarg ingithem.. The. coke particles.that.become.` cooledby giving.` up; heat inf thei operation, are recycled' to' the:

burner in'. a iluidized stream, the: processrbeingfazcona tinuous'ione.. The efrlluentisi withdrawn from the reactor." andscrubbed; to cool it, andmay. thenzbe given further: treatment as desired; excess cokeis` alsowithdrawnlfrom" thesystem asiaby-product.

Aiserious':problem'thathas.notheretoforebeen solved;` 1 is. how.' to` transferir/the.` reactor effluentltlie:cracked-Vv ice apparatusihad been constructed; sof the/solution of the problem hasbecome more dicult andl morel necessary.

than before..v

vOne object of the invention, therefore, is toconne the production of cokeftozthe: coke bed inthe cokin'g,` `reactor and vto' inhibit subsequent reactions from produoinglco'ke in the effluent from the reactor.

Another object of the invention is to provide ay method andapparatus for; inl'iibitingy the deposition of` coke, however` formed; in the eflluent transfer lines, includinggth'efcyclones, between ,the` coking'V reactor and thevscrubber..

'Another object yofi the inventionis to inhibit therdepo-T sitionV of coke on the walls Iof the dilute-phase'section.l

and 'so that. the-coke itself can be returned to -the-cokei bed in ther-coke reactor.k

Another objectfof` the invention, the -achievement'off which. is necessary to achieve the foregoingv objects;` is. t provideV afsystem by which ythe eiiuenty from thefcokingr reactor' isY transmitted into the'scrubber without hav ingits temperature lowered and without having'itstemperature greatly-raised or-.subjected to"any.suddenzchange= before quenching.

It .has beenv found .thattherrefuent will inevitablyxpr'o duce woke-if .there is any drop in"v they temperature ofithe^4 eliluentA prior to: its f quenching: Experience"indicatest vapors and high-boiling uncracked asphaltic compounds? producedin the cokingreactor. and' carried offin the formxoffan entrainedk mist) from: the reactor. `tr'the':` scrubber (where the effluent is cooled by'quenchingl` without depositingl coke inthe transfer lines; There,; coke has built 'up in the4 cyclonesfand theirn exhaust. risers to such anzextent that it` greatly Yshortenedthe' runs'ithat .couldberrnade before having to stop the apparatus .and clean out the cokeY deposits;

Coke has' also. been deposited on the walls ofY the* dilutefphase sectionvof the reactor and on yther bottom side of the lower baffles `in the scrubber. Furthermore;`

the coke` carried over in the eiiluent has accumulated in the: bottom of the scrubber and has plugged the suc'- tion lines to the quench-oil and recycle pumps.-

Moreover, evidence indicates that, inaddition vto'the coke carried into the transfer lines from theV reactor,v

considerable coke has been produced right in the-trans" fer lines, due to reactions insidethe cyclones'and their This coke has begun to deposit on the Wallsv up rapidly until they closed olf one or more of the-y cyclones; iinally the entire apparatus had to. beclosedV down, cooled, and the coke laboriously chipped away. This evidence as to the formation of coke elsewhere than in the reactor contradicts what was believedl before and.

therefore nullifes some vof the assumptionsron which'v the.k

thatpthe-etll'uent; should. lnot dropfeven one'degree in:V

temperature until it is instantaneously quenchedfain'thefl atedphenomenom lies partly;v insthe Vfacttliat .-themjeactorrV v efujentis. not Vaztrue vapor but 'is ratherra-:mixture .gt cracked:` vapors` and.'.entrainedl."higheboiling; unrackedf asphaltic compoundsin the foirn of a mist. It hasrb'eenif found that this;asphaltic:mistwillfcondense 'and form coke onanymetal surface cooler than the effluenter'rixs--T ture: Q nj order."topavoideareductionin Ytemperature,the temperature-of? th'eeluent should. be kept rising grad?V ually until' .it is` quickly cooled v by:quenching.; Yet fthe! mist'will alsofcrack andfdeposit coke if-itvisz subjectedv4 to-"excessively hightemperatures. VFor' example; `the`r cracking ofthismist proceeds-at. anzextremely fast rate when 1125? F'.coke actually contacts the reactor efluent:Y atthemouth of the cyclonefin a's'ystemfthat has .here-Y tofore been generally-used. lnwbrie-fg-hotfvaporsfshouldf netz contact cold metal, 1 and' cold vapors` should -znot-= con* tactflrot-.metal-.v

Another objectv :of thef invention;v therefore, .is tor= gradually raise vtheternperatur'eofA the leiuentfas itwrisesin the dilute or-vaporphase of theJ reactor. witlloutcontact` ing itdirectlywith freshly-heated-rcoke. g

I he method. of` this. invention. includes continuously` raisingthe-temperature of. the efuent as it rises inztheA reactors dilute phase, passes throughy the. cyclonesand is conducted into the scrubber. Preferably, the' heat necessary Vto produce this increase in' temperature. is. obtainedffrom freshly heated coke, direct fromV the heater,which.is kept separateY from the risingefuent by,` bafflingvit therefrom. The method'also callsforn conductinglthat`euentwhichcondenses away from the. lower part of "the scrubber. andv settling:v entrained coke out' therefrom, cooling th`e. coke-freedv oil` and'returning.

Patented July 26, 1960 achieved and byV which the method of the invention may be practiced involves several important changes in the structure of a uidized coking unit, namely, (1)v theprovision around at least the upper part of the cyclones of a baffle withsloping sides and ra depending cylindricalV skirt spaced relatively closely from the reactors innerl walls and extending down to a short distance only above the normal coke bed; (2) means for conducting some of the hot uidized coke particles from the burner into the coking reactor above the bathe and above the cyclone inlets, so that the coke passes down around portions of the cyclones and then down between the inner lined wall of the reactor and the skirt of the bale into the coke bed, thereby'heating the cyclones, the risers, and the bathe; (3) the provision of downwardly directed jets of steam at approximately 1200 F. at the bottom of the skirts to bar the entry of cracked effluent up into the downlowing heated coke; (4) the use of a novel outlet structure for the risers that lead from the cyclones and terminate in the scrubber, each riser being provided with jets projecting steam outwardly Vand upwardly around its exhaust opening; (5) the provision of a settler tank outside the scrubber, into which is conducted that euent which is fully condensed by the initial quenching, and wherein the quenched oil is cleaned for' return to the scrubber while the settled coke slurry is recycled to the coking reactor; (6) a novel arrangement of baiiles in the lower'part of the scrubber and the use therewith of additional quench-oil or low temperature steam.

Other objects and -advantages of the invention and its details of construction will be better understood from the following detailed description of a preferred embodiment thereof presented in accordance with the statute.

In the drawings: n

Fig. 1 is a view somewhat diagrammatic in form of and having what may be called a normal bed level 16 which varies up and down and bubbles considerably. The spray of liquid feed at 13 is distributed over the surface of coke particles in the bed 14. The small, hot coke particles act as heat sources to eect cracking of the feed, forming coke and a vaporized euent which Y leaves the reactor 10. The eluent exits through a bank a fluid coking apparatus of the type to which this in- Y Vention applies, including a coking reactor, a coke burner, and a scrubber, and including apparatus embodying the principles of this invention.

Fig. 2 is an enlarged view in elevation and in section of a portion ofthe upper end of the coking reactor of Fig. 1 and a portion of the lower end of the scrubber,

including apparatus embodying the principles of this invention.

Fig. 3 is a view in section taken along the line 3-3 inFig. 2.

The purpose of a fluidized coking installation like that shown in Fig. 1 is to treat the residual oils from petroleum rening processes to obtain upgraded, lighter products that can be introduced into thermal or catalytic cracking units. Some naphtha and gas fractions are also produced. As a by-product, coke is obtained in ne particles like sand. This process contrasts with those processes which terminate with an asphalt residue and is distinctive in giving both a greater total yield fromv the. crude oil and more salable and more valuable byproducts. It is distinguished from delayed coking processes by beinga continuous process.

As shown in Fig. 1, the coking installation normally comprises a reactor 10a heater 11, and a scrubber 12.l

The system is generally similar to a uidized catalytic cracking -unit but operates with coarser solids. In the reactor 10, hot oil feed at about 400600 F. from theY renery is sprayed at 13 through nozzles into a bed 14 of nely divided uidized coke at a temperature of about 900 to 1050 F. and kat a pressure somewhat above atmospheric. Throughout, the solid particles are uidized by steam, which is added at 15 near the lower end of the reactor 10 and elsewhere through the reactor, as well as by the cracked products which are generated in the bed of uidized coke. The coke in the reactor 10, therefore, acts substantially as a fluid, tending to boil of vcyclones 17 which separate entrained coke particles and return them to the bed 14, while the eluent ows up through risers 1S into the scrubber 12. In the scrub-V ber 12 the eiuent is cooled suddenly, by quenching, and is then passed to a fractionator (not shown) and a condenser (not shown), from which it is introduced into various phases of the refining process.

In the reactor 10 the decarbonization reaction simultaneously deposits a layer of coke on the particles in the bed 14. This deposit includes those components of the feed having ya high tendency to form coke, and the coking serves to remove them from the distillate products. Also, all but a minor part of the metallic contaminants and ash in the feed are retained in the coke, so that the eluent is thereby cleaned from the very high ash content of the pitch.

To obtain the hot coke needed in the reactor 10, part of the product coke formed therein is withdrawn from the lower end 20 and transferred as a steam-borne fluid, via a pipe 21 into the heater 11, which is also operated as a uidized bed. Chunks of coke unsuitable for fluidization and circulation may be removed from the reactor 10 through the valve 22.

Air is added tothe heater bed through the Yopening 23, some of the coke is burned, forming carbon dioxide and carbon monoxide and heating the bed to a temperature of approximately 1100 to 1200 F. The combustion products escape through the ue 24. An amount of coke weighing about 5 to 7 percent of the fresh feed oil from 13 is burned as coke in the heater 11 inY this reaction, and most of the remaining hot coke is recirculated to the reactor 10 through the conduits 25 and 26 to maintain the proper reaction temperature, steam being `added where needed to'maintain uidization. reaction in the reactor 10 cools the coke, the coolercoke is continuously being returned to the heater 11 'through the pipe 21, a stripper being provided above the reactor bottom wherein the hydrocarbon vapors vare displaced by steam to prevent their being carried over to the heater 11. Y

In the reactor 10, the particle size of the coke perpetually tends to grow as a result of the coke deposition described above. Since, as is well known, there is a desired maximum particle size, the larger particles are replaced by small seeds. This may be done by grinding or by other suitable means. Also, product coke is withdrawn from the burner 11 and sent to an 'elutriator 28 via a pipe 28a. In the elutriator 28 the product is cooled and washed by water. The elutriator 23 also serves to return finer particles to the burner-reactor system via the pipe 28b and provides for regulation of the size of the coke, the larger particles of which are withdrawn from the elutriator 28 through a conduit 28C at a safe temperature for handling.

So far, the description has related to the environment of the invention, in which are incorporated the novel features that will now be described. lt will be noted that the heated coke'particles from the burner 11 are returned to the reactor 10 through a major conduit 26 and a smaller conduit 2S. Heretofore, when two conduits have been used, the Vsmaller conduit conducted the co'kc up to the mouths of the cyclones 17 where it contacted the effluent. The purpose was to` inhibitcoke deposition on the interior surfaces of the coking vessel, including the cyclones, above the uid bed by maintaining, in the As the thereby removing carbon deposits, and to provide surfaces upon which the condensing vapors were absorbed; H owever, for reasons explained above, this prior-art expedient failed 'to solve the problem because its beneficial effects were, to a gre'at extent, countervailed by the formation of additional coke, due to the reaction produced by the sudden temperature change undergone by the effluent when 'it met the much hotter coke lfrom the burner, Also the 'introduction of freshly heated coke into the cyclone openings placed additional load on the cyclones and aggravated the carryover of entrained coke into the scrubber. In addition, the prior art placed a structure called an anti-coking baffle around the cyclones 17 and spaced from the upper wall of the reactor 1d, 'with the purpose of keeping. coke .from encrustingjthe top wall ofthe reactor` 10. The anti-coking balde defined Aan upper chamber from the remainder of the reactor, and hot steam was sent into this chamber. with the ideal-of keeping the baille wall hot Yenougl'l so that a minimum of coke would be-fdeposited thereon.' No coke was allowed to pass into the chamber above this anti-cokng' baffle, .The fore.- gingexplanation will help in appreciating my invention, wherein a'somewhat similar-appearing bathe is provided butin which an entirely diferent type of operation 'is achieved by important structural changes. n o

In the present invention (see Fig. 2), hot coke is carriedv in the pipe from the burner 11 to the reactor '150 through the reactor wall into an inlet pipe 31, the upper'portion 32l of which is substantially vertical,l and is conducted therein .up along the central .vertical axis .of the reactor lil'to a point nearthe veryftop of the reactor 10 where an inlet opening 33 is provided above .a baiile 34, Vwhich has aldierent structurefromgan fanticoking baa", The hot'coke from thev inlet pipe 31" is deposited above'th'e ballle34, filling the Aspace .35 .with coke.. The ybatllewt has an .uppe'rportion 36 provided with the inlet opening 33 'for the hot coke, a conical wall 37 extending down andout toward the reactors'` walls 30, and ar skirt 38 which depends from thelow'enfd ofthe conical portion 37 down to or below the level of the dip-leg outlets 3S* of the cyclones 17, whence the. coke particles separated out from the eflluent in the cyclones 17 are returned to the coke bed 14.

The coke that enters the space 35 thus surrounds at least the :upper portion of the cyclones 17 andthe lower portion 'of the cyclone risers (i8 and acts to gradually Iincrease the temperature of the efuent as Vit rises. kIf desired, the lowerk portions of the cyclones 17 down to the dip-leg 39a may also be enclosed by the bale v34. There will be some cooling of the coke as it falls from the top 36 ofthe baffle 34 to the coke bed level 16; there- ,'for'e, .since the coke is warmest at the top and cools as lit ows down, it maintains the temperature of the rising effluent at a gradually increasing value. Since its temperature vis increasing, the eiiluent cannot condense on the Walls -of the coke-heated transfer lines where it would vcoke and encrust the walls. Thus, the invention achieves I The 'steam in the'tubings 47 may be provided from the the important object of inhibiting the formation and deposition of coke in the effluent during its passage from the `entrance 46 to the cyclones 17 up to the bottom of the 'scrubber 12. This solves the problem of preventing coke deposition in the transfer lines, since the dry entrained Vof the reactor 1),- preventing the vaporousefuent from `cooling and 'depositing coke; and the baille separates the coke which happens in prior art devices Where they do come intocontact. f.

After the fluidized coke flows down the conical balli hot coke from the efduent, preventing the formation of portion 37, it passes between the skirt Vportion .38 and reactor innerwall 30. "The annular space 40 here is relatively narrow to prevent escape of effluent up therethrough, and the continuous downward flow ofcokealso preventseflluent from entering through-the' space 40. However, in addition, for use at the beginning of-operations,iat times whenthe coke flow may/be intermittent,v

and as a precautionary measure, `an annular tubing 4.1 is provided in the space 4t) around the bottom 42 of the skirt 38, and downwardly directedv -jets 43 of vsuperheated steam to prevent `anyeffluent from passing up through the stream of downowing coke into ,the space where it would tend to form coke and to cause plugging.` It shouldbe noted that the heated coke fro-mthe burner 11 is in the `form of. veryrhard particles which d o not stick to the walls of the reactor 10 or of the baffle 34. Only rthe newly, formed coke that would. be fproduced from the eiuent could` stick to thewalls and cause plugging, and that is: what thejets prevent,` o

- Thus, the effluent rises, asitshould, into the"space,44

in the :center of the reactor 19 .constituting the reactors an upwardly spiralling tubing 47. The steam in this Y tubing 47-main`tains Vthe temperature at the desired level.

samejsource as'thatv for the tubing 41. l .'Heretofore,gthe upper endvorf the riser v18 hasconsisted of an elbow, but this has been'found detrimental 'becauseit causes deposition' of coke `from the efu'ent at the funnel, 'due .to cooling thereof. Y.Various improvements 'havefbeenf suggested, but the present.invention provides ya. simpler and more useful structure` in which `the riser can extend vertically upwardly all the Wayv to its exhaust opening 49, which is the same diameter .as theremainder of the riser 18. The effluent is therefore conducted without meeting obstructions or restrictions vin the Vrisers 18, and. a .steadily rising temperature vis maintained, thereby eliminating substantially all the coke formation in the riser. To prevent the stream of exhaustedeuentffrom sucking in material in the scrubber 12, jets 5 0 spray steam, at approximately 1200 F., upwardly at about outwardly from the top of the-risers 18. Preferably, the jets S0 are disposed in a ring around 'the'outlet 49, as by providing them at Vthe .upper end of the coiled tubing .47, the Ylast .turn of which is horizontal andis at .the tip of the. outlet 49. Y 1

When the effluent enters the scrubber12 ,it is ,instantaneously quenched. While this instantaneous action vdoes not .produce any coke, the `condensed liquid that formerly collected on .the bottom Wall 5l' of the scrubber `12 did have .an adverse effect, since this cooler liquid necessarily cooled the risers 18. Since even a slight 'cooling 4action .leads to the formation of coke, itis desirable to eliminate'it -completely. Also, coke which 'accumulated therein-.tended-.to plug the pipes leadingto the pump foi-,the quench-oil, the quench-oil being obtainedrrfrorn the condensed. efuent.- Both these .adverse .effects are avoided by draining. the floor 51 and .conducting allthe condensedliquid from .the outwardly slopingJioo-r 5.1 ofthe scrubber 12 througha. conduitEZA Y into a settler tank 53, preferably .shaped generally .as .shownwith an upper cylindrical portion 54 .and a .lower conicalportion `55.

The condensed .eiiiuent. enters. the settler. 53 .at .about theupperend of the lower, conical portion 55." -The capacity of thesettler 53 `is large enough to give several minutes of settling, and the pressure iskept at the 'same value as that of the-scrubber 12 by a pressure-equalizing conduit 56 at its upper end. The coke slurry settles to the Vbottom and is Vrecycled by a pump 59`to the reactor 10 through the bottom outlet 57 and conduit 58. The clean quenched oil is withdrawn through a conduit 60 from the upper cylindrical portion 54 of the settler 53, is forced by a pump 61 to a cooler 62 and, cooled, is returned to the scrubber 12 through a conduit 63 for use as quench-oil.

That effluent which did not condense has in the meantime been passing upwardly in the scrubber 12. As it does so, it is continually quenched and cooled by sprays of oil fromthe conduit 63. Sheds 64 send the eiuent on a labyrinthine path that assures adequate contact with the quench-oil. The present invention provides, in addition, a group of bottom sheds or trays 65 and spray nozzles 66 below each lower tray 65 to wet the lower surface 67 of the lbottom trays 65 and therebyprevent coking at thatpoint by protecting them with a lm of cool oil. These nozzles 66 may be supplied'with quenchoil from the conduit 63 through a branch conduit 68 (in which event they are turned ononly after the unit is sending up enough eiiluent to keep oil fromV dripping back into the risers 18). Or they may be supplied from the beginning with low pressure, relatively. cool (e.g. 309 F.) steam from the conduit 69. The steam may be used instead of'oil, or a switchover to oil may be made after the unit vis in full operation by turning Vthe threeway Vvalve 70. The pipes to the nozzles 6&5V preferably enter radially through the scrubber walls, so that they are as short as possible. These bottom trays 65 Aare preferably placed vertically above the risers 18 and serve to prevent quench liquid from above from falling into the. exhaust openings 49. While most of the trays 64 in the scrubber are normally inverted V-troughs,4 the bottom trays 65 may be, and preferably are, cone-shaped so Vthat they better overlie the exhaust openings 49.

In operation, the fresh-feed material is sprayed at 13 into the bed of iluidized coke 14, while steam is put in at 15 `and elsewhere. Coke is constantly being drained from the reactor 1li and conducted through the conduit 21 to the heater 11 where some of the coke is burned to -heat the remainder, and hot coke is returned from the heater 11 via conduits 25 and 26. The coke returning through the conduit 25 flows into the space 35 above the baie 34 and serves to heat the baffle 34 and the efliuent flowing up through dilute phase sections 44 and 45 of the reactor, the risers 1S, and at least the upper part of the cyclones 17. The flow of coke downwardly -means that the portion at the top is hottest and therefore the eluent is hottest at kthe top. However, the `temperature increase is a gradual one.

The hot coke flows on down through the space 40 between the reactor wall and the baie skirt 38, whence it falls onto the normal coke bed 16. The steam sprays 43 prevent any partially crackedefuent which `rises from the normal coke bed level 16 from flowing up through the space -and depositing coke therein.- The effluent flows up through the space 44, 45 inthe center of the upper end of the reactor. 10 and enters theseveral openings 46 into the .cyclones 17. Coke particles are removed in the normal manner and are returned to the coke bed Vthrough the` cyclones lower end 39.. The' eiuent, freed from these coke particles, flows up through the risers 1S while its temperature is very gradually increased and then it is expelled through the outletl 49 into Ythe lower end of the `scrubber 12. At .the outlet 49steam sprays 50 protect the risers 18 and the eiuent therein from sucking in drops of condensate, and the overlying Vsheds 65 prevent oil from falling in.- The sprays 66 of steam or quench-oil prevent the formation of coke on the bottom surface 67 of the sheds @65. which themselves,

vtogether with the other sheds 64 thereabove, vserve to Aassure contact between `the quench-oil and the effluent.

Eluent which condenses and Settles on the licor 51 is piped out therefrom by the conduit 52. into the settler tank 53. From there clean quench-,oil is withdrawn and cooled for return into the scrubber 12. From the bottom of the 'settler tank 53 a slurry containing most of the coke in the condensed eluent is returned to about the middle of the coke bed 14 for further processing.

The foregoing description of the apparatus andv its operation has also included numerous indications of my novel method. For one thing, the method includes subjecting the rising eiiiuent to continually gradually rising temperatures while passing it through the reactors dilute phase, separating it from entrained cokeparticles, and conveying -it into the scrubbing zone'. lt obtains the .desired temperature conditions by flowing a stream of heatedv coke downwardly around the transfer lines, cyclones Further, the method of this inventionV involves convey.

ing condensed eiuent away from the scrubber and settling it, separating the coke slurry from substantially cokefree oil to use as quenching oil, and returning the coke slurry to the coke reacting zone.

Practice of the method of this invention, particularly when used in conjunction with the apparatus heretofore described, results in a substantial reduction of coke formation and coke carry-over between the reactorrand the scrubber. Moreover, thisV invention makes it possible to operate the coking apparatus substantially continuously without having to make frequentI stops for slowly ,cleaning out coke `deposits after having allowed the apparatus to cool Vfor many hours.

To those skilled in the art to which this invention re lates, many changes in construction and widely differing embodiments and applications of the invention will suglgest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

I claim:

l. In a coking process for upgrading heavy petroleum fractions, in which a luidized bed of heated coke is continuously sprayed with a fresh feed of said fractions to produce thermal cracking thereof into a vaporous eiiiuent and additional coke, said vaporous effluent being separated from coke particles and transferred upwardly to a quenching zone while the coke is cycled through a heating zone for reuse; the novel steps of conveying freshly heated coke in a downwardly and outwardly flowing stream around and separated from the upwardly owing effluent so as to heat it without direct contract therebetween and so that the temperature imparted to said efuent is highest at the top and rises gradually and consistently during the upward passage of said eluent; maintaining said separation to a point just above the bed level; and there adding said downwardly flowing stream of coke to said coke bed, while spraying jets of steam downwardly at the point where the separation of said eiuent from said downwardly iiowing stream of coke terminates, to direct said eiiluent away from said stream.

2. ln an apparatus for upgrading high-boiling petroleum fractions by a fluidized coking process and including a coking reactor with a generally cylindrical wall enclosing a coke bed portion and a dilute phase portion above the coke bed portion, with a cyclone means therein for separating coke particles from the effluent and returning the coke particles to said coke bed, a scrubber therewith of a series of upwardly and outwardly directed steam jets around the outlet of the riser means in the scrubber for preventing the sucking of drops of quenched efuent into the rim of said outlet, shed means in said scrubber spaced a short distance vertically above the-outlet of said riser, and means to spray fluid cooler than said effluent on the lower surface of said shed means, said shed means protecting said riser outlet from falling drops of condensed eiuent and said spray means protecting said lower surface of said shed means -against the formation of coke thereon.

3. In an apparatus for upgrading high-boiling petroleum fractions by a fluidized coking process and including a coking reactor with a generally cylindrical wall enclosing a coke bed portion and a dilute phase portion above the coke bed portion with a cyclone means vtherein for separating coke particles from the efuent and returning the coke particles to said coke bed, and a scrubber above said reactor where said eiiiuent is quenched,

the combination of a straight vertical riser conducting said effluent along a straight vertical path from each said cyclone means into said scrubber, said riser having an open upper end for vertical discharge of said eluent, and a series of upwardly and outwardly directed steam jets around `and on said riser outlet for preventing quenched eiiiuent from being sucked into said outlet. i

4. In aV hydrocarbon oil fluid coking vessel which com-V prises means for establishing and maintaining a duid bed of particulate solids at a coking temperature in the lower portion with a disperse zone thereabove, cyclone sepa rating means in the upper portion of said vessel with a dependent dip-leg and means for injecting liquid hydrocarbon oil into an intermediate portion of' said uid bed,

the improvement which comprises a substantially conical partition separating said cyclone means from said disperse zone and continuous with a substantially cylindrical partition separating said disperse phase from the inner wall of said vessel providing an annular space therebetween terminating immediately above said bed at a level no higher than the lower end of said dip-leg, cyclone entrance means extending through said baffle and connecting said cyclone means with said disperse zone, and inlet conduit means for admitting a stream composed mainly of heated'particulate solids into the space between said conical baile and the upper end of said vessel at a point adjacent the apex of said conical bale whereby the cyclones and the Walls of the disperse zone are heated by external contact with the hot solids descending from said apex to said bed.

References Cited in the le of this patent UNITED STATES PATENTS Re.`16,252 Catlin Dec. 12, 1926 1,790,824 Loebell Feb. 3, 1931 2,661,324 Lefer Dec. `1, Y1953 2,734,852 Moser Feb. 14,v 1956 2,763,601 Martin Sept. 18, 1956 l2,789,082, Barr Apr. 16, 1957 2,791,549 Jahnig May 7, 1957 2,793,173 Fritz May 21, 1957 2,810,679 Haig Oct. 22, 1957 2,859,168 Downing et al. Nov. 4, 1958 2,881,130 Pfeiffer et al. Apr. 7, 1959 Polack June 16, 1959 

1. IN A COKING PROCESS FOR UPGRADING HEAVY PETROLEUM FRACTIONS, IN WHICH A FLUIDIZED BED OF HEATED COKE IS CONTINUOUSLY SPRAYED WITH A FRESH FEED OF SAID FRACTIONS TO PRODUCE THERMAL CRACKING THEREOF INTO A VAPOROUS EFFLUENT AND ADDITIONAL COKE, SAID VAPOROUS EFFLUENT BEING SEPARATED FROM COKE PARTICLES AND TRANSFERRED UPWARDLY TO A QUENCHING ZONE WHILE THE COKE IS CYCLED THROUGH A HEATING ZONE FOR REUSE, THE NOVEL STEPS OF CONVEYING FRESHLY HEATED COKE IN A DOWNWARDLY AND OUTWARDLY FLOWING STREAM AROUND AND SEPARATED FROM THE UPWARDLY FLOWING EFFLUENT SO AS TO HEAT IT WITHOUT DIRECT CONTACT THEREBETWEEN AND SO THAT THE TEMPERATURE IMPARTED TO SAID EFFLUENT IS HIGHEST AT THE TOP AND RISES GRADUALLY AND CONSISTENTLY DURING THE UPWARD PASSAGE OF SAID EFFLUENT, MAINTAINING SAID SEPARATION TO A POINT JUST ABOVE THE BED LEVEL, AND THERE ADDING SAID DOWNWARDLY FLOWING STREAM OF COKE TO SAID COKE BED, WHILE SPRAYING JETS OF STREAM DOWNWARDLY AT THE POINT WHERE THE SEPARATION OF SAID EFFLUENT FROM SAID DOWNWARDLY FLOWING STREAM OF 